The present studies have been undertaken to provide basic information on the biochemistry and function of the retinal pigment epithelium. In particular, the enzymology of rod outer segment degradation is being examined, using pigment epithelial cells and homogenates isolated from cattle eyes. Labeled substrates are used to trace the degradation of the principal phospholipids of the rod outer segments, namely phosphatidylcholine and phosphatidyl-ethanolamine. Another major problem under investigation is the metabolism, storage, distribution and transport of vitamin A compounds in the pigment epithelium, the retina and the interphotoreceptor matrix that lies between them. An unerstanding of the interdependence of, and interaction between, the neural retina and the adjacent pigment epithelial cell layer will hopefully provide a basis for studying the pathogenesis of a number of degenerative diseases of the retina. BIBLIOGRAPHIC REFERENCES: Berman, Elaine R. Diagnosis of metabolic eye disease by chemical analysis of serum, leukocytes and skin fibroblast culture, in Birth Defects: Original Article Series, Vol. XII, No. 3, pp. 15-51, 1976. Rothman, H., Feeney, L. and Berman, E.R. The retinal pigment epithelium: analytical subcellular fractionation with special reference to acid lipase. Exp. Eye Res. 22, 519-532 (1976).